This invention relates to a fork lift truck attachment having forks which can be shifted laterally relative to a supporting carriage, can be pivoted 90 degrees to either side of a forward position and which can also be adjusted for side tilt and fore and aft tilt.
U.S. Pat. No. 3,106,305 issued Aug. 23, 1962 to W. F. Gehring for an Industrial Lift Truck shows a lift truck attachment having forks which can be shifted laterally relative to a carriage and which can be pivoted 90 degrees to either side of a forward position.
U.S. Pat. No. 3,572,530 issued Mar. 30, 1971 to F. F. Ohntrup et al. for an Industrial Truck having forks which can be shifted laterally relative to a carriage, which can be pivoted 90 degrees to either side of a forward position and which can be adjusted for fore and aft tilt.
Fork lift trucks are well known for their ability to handle a wide variety of warehousing jobs. They have also found application in outdoor storage facilities. Their use tends to be restricted to movement of loads over floors and terrain which are relatively level. There are a wide variety of products which may be packaged for outdoor lift truck movement such as bricks, concrete blocks, flat rocks and other landscaping products, heat pumps, roofing, and other building items. Heretofore the use of a fork lift truck was limited because of uneven ground or because the load to be moved was on a different slope than the lift truck as, for instance, when the ground supporting the lift truck is not parallel with a building floor or scaffold.
This invention permits a fork lift truck to be used for many material handling tasks which were previously beyond its capability. A relatively wide tool support is secured to the lift truck carriage, which is mounted for vertical movement on the mast. A forward extending load arm is slidingly mounted on the tool support and is shiftable laterally by a power actuator. The forward end of the load arm supports a sub frame for pivotal movement by a power actuator about a vertical axis and the sub frame pivotally supports the top of a hinge plate for swinging movement about a horizontal axis disposed forward of the vertical axis, the swinging movement being controlled by an extensible and contractible fluid actuator. The hinge plate pivotally supports a fork mounting wall for pivotal movement about a horizontal axis at right angles to the fork mounting wall and a power actuator is interposed between the hinge plate and the fork mounting wall to selectively pivot the fork mounting wall relative to the hinge plate. This construction allows the lift truck operator to maintain the fork tines in a horizontal plane even though the lift truck may be on a terrain sloping in a fore and aft direction and sloping laterally. This attachment, for instance, permits the lift truck to safely deliver a pallet of construction materials or other construction items to a scaffold even though the support for the lift truck is not parallel to the scaffold floor. This attachment also allows the forks to be adjusted for insertion in a pallet or beneath a load in a manner in which the load or pallet is supported by both forks as it is picked up. Likewise when the support for the load or pallet is on a plane different than the plane of the support for the lift truck, the forks can be adjusted to deposit a load or pallet in a gentle manner.